Aquatic Plants with Miracle Grow

**jamesstill84** · 08-30-2009, 11:08 PM

If you didn't have any fish or inverts or anything in a tank with plants, could you dose it with Miracle Grow? I sat a tub outside to try to grow plants in. It's got top soil substrate with water that I took from the aquariums during the weekly water changes.

I was thinking of dosing it with Miracle Grow just to see how quickly they would grow under those conditions. I won't be putting any creatures in the tub with the plants.

Has anyone ever done this?

**theredchaser** · 08-31-2009, 4:42 AM

Hmm.. well I googled and the first link has many things to say about Miracle-gro:

"Miracle-Gro is a synthetic fertilizer that contains ammonium phosphate and several other chemicals that can be toxic to your soil and plants. ... The application has to be timed carefully and placed properly to avoid burning the leaves and roots . . . . In addition, ammonium tends to inhibit the release of . . . potassium

Miracle-Gro contains muriate of potash, which contains excess chlorine that will burn plants and inhibit the uptake of nitrogen"

I see 2 big problems...
1) ammonium-phosphate: its really easy to overdose ammonium, and will also turn your pH very acidic very quickly. NH4+ + H20 <---> NH3 + H3O+ In addition to to the acidic water burning your plants, the elevated levels of phosphate will invite tons of algae.

2) muriate of potash: same thing as KCl. The potassium is good, but the chlorine is very very bad... Considering that KCl will dissociate completely, you will definitely have elevated levels of chlorine.

I'm not sure if Miracle-gro lists their chemical concentrations so dosing might be tough to figure out. My guess is that with a light dosing your plants will grow but you'll need water changes for additional dosing to prevent the toxic chemicals from accumulating too much. There's definitely better ways to do ferts but it might be an interesting experiment.

**jmhart** · 08-31-2009, 7:56 AM

Miracle grow is simply a lazy mans fertilizer. I don't mean any offense. It's intended to make fertilizing easy. If you already fertilize your plants with NPK, miracle grow won't help.

**Wycco** · 08-31-2009, 8:44 AM

Even toxicity aside- I'd be worried that with the phosphates and balance of a fert designed for land plants I'd see more green water and algae growth than I would plant growth.

**DeeDeeK** · 08-31-2009, 9:27 AM

Wouldn't the Cl from the KCl degass as the K is taken out of solution by the plants? I'd bet that it does. Of course, KCl is awfully chemically similar to NaCl, which tends to annoy freshwater plants.

As for phosphates, they don't make algae grow just at random. They need to be available (not already taken up by aquatic plants) and there needs to be sufficient other macro and micro nutrients available. By not over fertilizing, this could be avoided.

Also, a nice rich community of aquatic plants will be putting out enough allelopathic chemicals to suppress the growth of algae.

Still, you couldn't pay me to put miracle grow in my tank! I'm excited to read about how it works, though!

**angyles** · 08-31-2009, 10:02 AM

Aside from the other comments here, I wouldn't because it's dyed blue and turns your water blue.

**Pixie_84** · 08-31-2009, 10:11 AM

Too bad this couldn't be that cheap replacement you were seeking to have. Maybe something will turn up.

**dundadundun** · 08-31-2009, 11:00 AM

a couple years back i read in a few places that jobes fertilizer sticks for ferns and palms was a good option for a substrate fert. this does nothing for your water column and i'm sure it's debatable and i have not tried it myself. i would check out aquariumfertilizer.com if i were you.

**247Plants** · 08-31-2009, 11:01 AM

Originally Posted by DeeDeeK

As for phosphates, they don't make algae grow just at random. They need to be available (not already taken up by aquatic plants) and there needs to be sufficient other macro and micro nutrients available. By not over fertilizing, this could be avoided.

Also, a nice rich community of aquatic plants will be putting out enough allelopathic chemicals to suppress the growth of algae.

First part isnt necessarily true. If you look into EI or PPD dosing the deal is to keep fert levels elevated to the point that the plants continuously outcompete the algae.

Second part is debatable. Sure it has been shown that a few aquarium plants available can emit them, however it is highly unlikely that our tanks can develop any decent amount.

Miracle grow is entirely too strong. Pretty much any fertilizer designed for terrestrials is going to be way overkill for aquarium plants. The only exception I know of is using pieces of jobe sticks in the substrate like root tabs.

**jamesstill84** · 08-31-2009, 11:12 AM

It was just going to be an experiment. The "tank" is a plastic Tupperware container of about 30 gallons. It's just some random plants that I was going to toss out until I thought this up. I wasn't about to waste Flourish on this "experiment", that's why I was just going to go with the Miracle Gro. I'll figure something else out.

Thanks for the all input guys and gals! It's much appreciated!